Event:
Pope Pius XII publishes his 1st encyclical Summi pontificatus
More Notable Events on October 20:
1979 John F. Kennedy Library dedicated in Boston
1973 Queen Elizabeth II opens Sydney Opera House
1968 Jacqueline Kennedy marries Aristotle Onassis
1818 49th parallel forms as border between U.S. and Canada
1803 U.S. Senate ratifies Louisiana Purchase
